Fuel injection pump with fuel cut-off device



Se t. 25, 1962 N. w. BOSTWICK 3,055,305

FUEL INJECTION PUMP WITH FUEL CUT-OFF DEVICE Filed Oct. 21, 1958 4 Sheets-Sheet 1 INVENTOR NORVAN W. BOSTWICK BY w wan. mze

ATTORNEYS.

'N. w. BOSTWICK 3,055,305

FUEL INJECTION PUMP WITH FUEL CUT-OFF DEVICE 4 Sheets-Sheet 2 F IG. 2.

Sept. 25, .1962

Filed Oct. 21, .1958

INVENT NORVAN w. TWICK MM WY AWM ATTORNEYS.

p 1962 N. w. BOSTWICK I 3,055,305

FUEL INJECTION PUMP WITH FUEL CUT-OFF DEVICE Filed Oct. 21, 1958 4 Sheets-Sheet 3 INVENTOR NORVAN w. BOSTWICK BY Ww-Lmr r ATTORNEYS.

Sept. 25, 1962 N. w. BOSTWICK 3, 55,305

FUEL INJECTION PUMP WITH FUEL CUT-OFF DEVICE Filed Oct. 21, 1958 4 Sheets-Sheet 4 INVENTOR NORVAN w. BOSTWICK BY W wzw rm ATTORNEYS.

3,055,305 Patented Sept. 25, 1962 fine York

Filed Oct. 21, 1958, Ser. No. 768,655 13 Claims. (Cl. 10341) This invention relates to fuel injection pumps for internal combustion engines wherein means are provided for operating one or more pump members to effect delivery of fuel as a function of intake manifold air density of the engine, and in particular, the invention involves novel and improved structure and means for cutting off the delivery of fuel to the engine without having to cut off the ignition.

A fuel injection pump incorporating fuel cutoff operation pursuant to the principles of the instant invention contemplates use in a system which does away with the conventional carburetor. For convenience of explanation the invention will be described with reference to a specific type of injection pump system employed in an automotive installation. However, it will appear from the description that the invention is applicable to all fuel injection systems of the general type referred to herein.

The fuel injection pump includes an oil operated servo interconnected to regulate the pumps metering chambers in order to deliver metered quantities of fuel to the engine for combustion. The servo is regulated by a capsule assembly, which assembly is adapted to sense manifold air pressure and its temperature. As long as manifold pressure and temperature afford a true criterion of the amount of air induced by the engine cylinders per cycle, the fuel pump will supply an optimum fuel to air ratio in accordance with the air consumed per cycle by the engine. As understood in the art, the pump has a fuel distributing valve eccentrically mounted to undergo hypotrochoid movement wherein a lapping action takes place between the opposed valve faces and the cooperating bearing faces of the pump structure. During such valve movement a ring of outer teeth on the valve meshes with a surrounding but stationary toothed annulus such that the metering chambers are individually interconnected in a desired sequence alternately with a fuel supply and then with one and then the other of discharge lines leading to respective engine cylinders.

In many applications of a fuel system for aircraft or land vehicles, the fuel injection pump has to incorporate provisions wherein its delivery of fuel to the power unit can be shut off in order to stop the engine without having to cut ignition. Various means for achieving this have been adopted in the past, none of which have proved wholly satisfactory.

Accordingly it is the principal object of the present invention to provide an improved fuel injection pump for internal combustion engines adapted to afford simple, thoroughly reliable and effective means for cutting off the delivery of fuel to the engine power unit without having to cut the engine ignition.

It is a further object of the invention to provide an improved fuel injection pump of the general type referred to herein employing novel means for cutting off the delivery of fuel to the engine power unit when desired by the engine operator or otherwise automatically without having to cut off engine ignition and which fuel injection pump system is readily adaptable for use in aircraft or land vehicle installations.

Ordinarily a small torque is required to effect fuel cutoff operation for an injection pump of the type contemplated herein at engine speeds in the nature of 800 to 1000 rpm. On the other hand, the torque required to effect cutoff at engine cranking speed, in the order of 50 r.p.m., rises sharply when the engine is to be purged at this relatively low operating speed. Similarly when the engine is brought to a stop in cutoff position, it is also necessary to have a relatively high torque in order to start up the engine. Accordingly it is a further object of the instant invention to provide an improved fuel injection pump incorporating mechanically simple and yet effective means for cutting off the delivery of fuel to the engine power unit without cutting its ignition for operation at relatively high engine speeds and for the relatively low engine cranking speed. In addition the improved pump also permits the engine to be started after it was stopped in cutoff position.

In furtherance of the preceding object it is a further object of the invention to provide an improved fuel injection pump affording fuel cutoff operation wherein the torque required for converting normal pump operation to cutoff operation and returning said pump to normal operation is furnished by the engine itself and thus eliminates the need of external sources of torque to effect cutoff operation which allows the additional advantage of providing a compact fuel injection pump where space requirements are very much restricted.

It is a further object of the instant invention to provide a fuel injection pump affording cutoff operation wherein an eccentrically mounted fuel distributing valve having suitably disposed ports undergoes hypotrochoid movement as its ring of outer teeth meshes with the toothed annulus of a gear ring such that the metering chambers of the pump are individually interconnected in a desired sequence alternately with a fuel supply and then one and then the other of pump discharge lines leading to respective engine cylinders. The pump includes means for moving said gear ring through predetermined angular distances from one to another of a plurality of positions thereby effecting corresponding shift to the valve such that pump operation alternates from normal operation to fuel cutoff operation respectively.

In furtherance of the preceding object it is a further object of the instant invention to employ a pinion adapted to engage the outer toothed annulus of the gear ring, which pinion is keyed to a locking wheel. The locking wheel in turn is adapted to engage alternately two predeterminedly spaced apart teeth of a rocker arm such that upon engagement of the first of said teeth, the wheel and pinion assembly maintains the gear ring stationary to cause the pump to deliver fuel to the engine; and upon escapement of locking wheel from engagement with the first tooth, the gear ring by reason of the force furnished by the engine drive shaft is permitted to turn so that the pump assumes fuel cutoff operation upon engagement with the second of said teeth wherein spill passages suitably disposed in the pump register with the metering chambers in order to return the fuel trapped therein to the fuel source during cutoff operation.

It is a further object of the instant invention to employ a solenoid which may be energized by the operator of engine power unit and which solenoid furnishes lineal movement in order to pivot the rocker arm to effect alternately engagement and escapement of first one and then the other of the rocker arm teeth with respect to the locking wheel as described in the foregoing paragraph wherein the torque for turning gear ring, the pinion and locking wheel assembly, and the generator for energizing the solenoid is furnished by the engine to provide a relatively self contained fuel pump.

It is a further object of the instant invention to provide improved means for effecting a cutoff phase of operation in fuel injection pumps of the type generally referred to 3 herein, which pumps are particularly suitable for automotive installations and may be easily designed to accommodate engines employing any number of cylinders.

Further objects and advantages will become apparent from the following description of the invention taken in conjunction with the figures, in which,

FIG. 1 is a longitudinal view in section of a fuel injection pump embodying the instant invention;

FIG. 2 is an end view partly cut away and in section illustrating the locking wheel and rocker arm assembly and its operatively associated solenoid, which figure is taken along line 22 of FIG. 1;

FIG. 3 is a plan view in section taken along line 33 of FIG. 1 and illustrates a plane extending through the disc shaped valve of the fuel injection pump;

FIG. 4 is a fragmentary development in perspective illustrating the operating relationship for the valve, gear ring and pinion locking assembly;

FIG. 5 is a plan view looking at the plunger bearing face of a six cylinder fuel injection pump against which the arcuate slotted valve face laps and, in addition, illustrates the spill slots on said bearing face for returning fuel to the fuel supply when the pump is set for fuel cutoff operation; FIG. 5a is a plan view of the face of the distributor block for the six cylinder engine pump and shows three spill passages employed therein for the purpose of returning fuel to the fuel supply to avoid hydraulic lock;

FIG. 6 shows a plan view of the valve looking toward the distributor block end of a six cylinder pump and illustrates the trace of an arcuate slot with respect to a metering chamber, its correlated discharge ports and the spill slots wherein the pump is set for normal fuel distribution operation; the. metering chambers and one group of spill slots are shown in phantom because they lie in the plane above the valve, whereas the discharge ports and the other group of spill slots are shown in dashed lines to indicate that they lie in a plane below the valve;

FIG. 7 corresponds to FIG. 6 except that it shows the relationship of the above noted components when the pump is set for fuel cutoff operation, in which case the spill ports in the plunger block face register with the valve slot during a sector of its travel as shown in figure; and

FIGS. 8 and 9 correspond to the illustration depicted in FIGS. 6 and 7 except that FIGS. 8 and 9 illustrate a pump structure for an eight cylinder engine.

Referring now to the figures, the fuel injection pump is made up of a housing 21 provided at one end with a capsule pressure chamber 22 and suitably sealed first and second interior servo operating chambers 23, 24 in its center portion. A main drive shaft 25 extends into housing 21 from its distributor block end and passes through chambers 23, 24. The exterior end of drive shaft 25 is arranged to be driven by the engine (not shown) in a well-known and suitable manner. Housing 21 is also provided with an internal cavity 26 formed in part by parallel opposed bearing faces 27, 28 separating the plunger block portion 29' of pump housing 21 from the distributor block portion 30 thereof. A plurality of metering chambers 31, 32 are disposed in the plunger block portion 29 of housing 21 and are arranged in a circle about .a common longitudinal axis 33. Two such metering chambers are shown in FIG. 1. However, the number of chambers will vary in accordance with the operational requirements determined by the particular engine and as noted further with respect to the embodiments of FIGS. 6 through 9. Each metering chamber is provided with a narrow port end, 31, 32 in bearing face 27 on the plunger block side of cavity 26.

A disc shaped distributing valve 34 is slidably mounted on an eccentric 35 which eccentric 35 is fixed to drive shaft 25 to turn therewith. Valve 34 is slidably seated between opposed bearing faces 27, 28 and has an annulus of teeth 36 on its outer periphery. In its preferred embodiment, valve 34 has eight mutually spaced apart arcuate or kidney shaped slots 37 formed as concentrically disposed recesses in the valve end face disposed to lap against plunger block bearing face 27. The use of eight slots 37 as shown herein is a matter of choice and is merely incidental to the practice of the instant invention. Moreover, it will be understood that the formation of slots 37 as arcuate shape recesses as shown herein, provides optimum communication between the metering chambers with yet to be described discharge passages so as to assure a favorable fuel distribution as understood by those skilled in the art.

Alternating adjacent ends of arcuate slots 37 are provided with through drillings 38 serving as passages extending axially through valve disc 34. Drillings 38 have open ends in the valve end face slidably lapping distributor block bearing face 28. A gear ring 39 is also mounted between bearing faces 27, 28 for rotation about axis 33. Gear ring 39 has an inner annulus of teeth 40 adapted to engage valve teeth 36. The ratio of pitch circle diameters of gear ring teeth 40 and valve teeth 36 is 9:8. The diameter of toothed annulus 40 is larger than the diameter of valve 34 engaged thereby to form a crescent shaped area 41 seen best in FIG. 3. Gear ring 40 is also provided with a toothed annulus 53 on its outer periphery for the purpose of imparting annular displacement to ring 39 with respect to axis 33 in a manner described hereinafter. At the moment it will be assumed that gear ring 39 remains stationary.

Distributor block 30 is also furnished with a plurality of discharge passages 42, one of which is shown in FIG. l. The number of such passages corresponds to the number of cylinders in the engine. As illustrated by dashed lines in FIGS. 6 through 9, passages 42 have open port ends suitably disposed about axis 33 in bearing face 28 for supplying fuel to respective ones of the engine cylinders. Fuel supply lines 43 are adapted to couple respective discharge passages 42 to the correlated engine cylinders. Distributor block 30 is also provided with an intake passage 44 which communicates with an external pump (not shown) of any convenient type for the purpose of delivering a supply of fuel under pressure to crescent shaped space 41 around valve 34, that is to say, the region between the outer periphery 36 of valve disc 34 and inner annulus 40 of gear ring 39.

Rotation of drive shaft 25 in a given direction imparts hypotrochoid motion to valve 34 as the latter revolves with respect to axis 33 in a backwards sense, that is to say, in a direction opposite to the direction of turning of shaft 25 as toothed annulus 36 experiences a travelling toothed engagement with gear ring teeth 40. Due to the 9:8 ratio provided by the gearing, valve 34 creeps backwards by one-eighth of a revolution for each revolution of shaft 25. Consequently as shaft 25 undergoes successive revolutions of turning, successive ones of arcuate slots 37 line up to register with respective ones of said metering chambers. As a result, each metering chamber is individually interconnected in a desired sequence alternately with fuel intake port 44 and then certain of the discharge passages 42.

Each metering chamber is arranged with an actuated variable stroke plunger 45. Plungers 45 are actuated by a variable angled Wobble plate mechanism 46 provided with a curved portion slidably seated in a complementary mating socket 47 of housing 21. One or more return springs 48 are compressed between -a fixed portion of the chambers and the plunger faces. A flat forward face of wobble plate 46 is adapted to bear against plunger end 56 to impart desired reciprocating motion to plungers 45.

Wobble plate 46 is slidably mounted on an oblique skew shaft 49 by means of a ring 14 provided with an outer spherical surface mating with an internal spherical surface of wobble plate 46. Skew shaft 49 is an integral extension of a hydraulically regulated servo piston 50. Combined skew shaft 49 and piston 50 is slidably mounted upon drive shaft 25 for axial movement therealong. Shaft-piston 4950 is also keyed to drive shaft for driven rotation therewith. Piston 50 has a cylindrical apron 51 providing a sliding fit in a cylindrical bore portion 52 of housing 21. Servo piston 50 forms a displaceable pressure responsive member within cylindrical bore portion 52 and separates the forward and rear operating chambers 23, 24. Skew shaft 49 is adapted to impart a variable cranking motion to wobble plate 46. A change in plunger stroke is obtained by moving the center of wobble plate 46 off the longitudinal center line 33 of drive shaft 25 by virtue of axial movement of combined skew shaft and piston along shaft 25. This produces a change in the wobble plate angle relative to the plungers due to the slide movement of wobble plate in its socket 47. In a well known manner, rotation of skew shaft 49 and the offset wobble plate 46 causes reciprocating mo tion to be imparted to the spring biased plungers 45. Desired plunger stroke between maximum and minimum can be obtained by axial repositioning of skew shaft 49. The stroke of plungers 45 will be maximum when servo piston 50 is driven to its extreme forward or right-hand position as seen in FIG. 1, whereas, minimum stroke is realized when piston 50 is driven to its extreme rearward or left-hand position. FIG. 1 shows piston 50 almost at its extreme forward position.

Servo oil under system pressure is delivered by means of a suitable port 55 from the engine lubrication system to chamber 23. It will be understood that oil is normally passed through a filter, not shown, to insure freedom against carbon, sludge and other foreign matter. This oil passes into the space 23 containing wobble plate 46 and the plunger ends 56. Being at system pressure, the oil tends to force skew shaft 49 with its integral servo piston 50 toward its rearward position, thus reducing the stroke of the pump plungers 45 and compressing one or more control springs 57. Control springs 57 are mounted over shaft 25 and are compressed between the upper side of servo piston 50 and a valve 58, which valve 58 will be described further hereinafter. Oil will flow into chamber 24 on the rear side of servo piston 50 by means of a cross hole 59 and an axial bore 60 in drive shaft 25. When oil flows freely in this manner, hydraulic pressure will increase on the rearward side of servo piston 50 until it equals that on the forward side. Oil flow from bore 60 is controlled by the longitudinally displaceable valve 58 which partially obstructs such flow by coaction with the opposed orifice 61 at the end of axial bore 60. Control springs 57 are compressed against valve 58 to force skew shaft 49 toward full stroke position. Springs 57 also tend to force valve 58 off its seat 61 to open the oil passage between operating chambers 23 and 24. With no oil pressure difference between the two chambers, control springs 57 will force skew shaft 49 to full stroke position. The servo oil is drained and returned to the engine lubrication system via a convenient series of passages 62a, 62b, 62c and 62d. It will be understood that the latter passage in housing structure 21 is interconnected in some convenient manner with the lubrication system.

Valve 58 is mounted on a translational spindle 63 which passes through a cover plate 64 and into the suitably sealed capsule chamber 22. A ball bearing thrust assembly 65 is mounted on the end of spindle 63 and bears against a stacked capsule assembly 66 made up of a plurality of stacked capsules 67 suspended in chamber 22. Stacked capsules 67 are mounted on a shank 68 adjustably sustended from a rear housing wall 69 by an adjustable anchoring nut 70. Adjustment of anchoring nut '76 permits longitudinal repositioning of capsule assembly 66 against thrust member 65.

Chamber 22 is adapted to sense air manifold pressure by suitable means such as a port 71 communicating with the air intake manifold not shown herein. Capsules 67 are interconnected interiorly and sealed in with dry nitrogen and respond to manifold air pressure variations exerted on the exterior surfaces thereof by corresponding expansion or contraction which results in a correlated movement being transmitted to thrust member 65 and valve 58. Accordingly, axial displacement of valve 58 is controlled by the combined responsive expansion and contraction motion of stack capsule assembly 66. In addition, the sealed-in interior of capsules 67 may be connected to a capillary tube 72 by means of a line 73 terminating in a nipple 74 threaded to housing wall 69. The other end of capillary tube 72, not shown herein, communicates with a temperature bulb filled with gas, as commonly known in the art, which bulb is located in the engine intake manifold.

A rising manifold temperature heats the temperature bulb and expands the dry nitrogen thus producing an increased pressure inside capsules 67 which results in capsule expansion. The combination of external and internal pressure on stacked capsules 67 determines its resultant pneumatic loading on valve 58 and serves as a metering signal which is transmitted to the servo system. Accordingly, changes in manifold pressure or temperature, or combinations thereof, cause expansion or contraction of capsules 67 with corresponding movement of oil servo valve 58 towards or away from its seat 61. This action restricts or increases, as the case may be, oil flow from the forward side 23 of servo piston 50 to the rearward side thereof 24 and thereby changes the oil pressure differential across the servo piston 50. Piston 50 and skew shaft 49 will change position accordingly until the force of the metering springs 57 hearing against valve 58 returns valve 58 to its normal position just off its seat 61 to allow a flow of oil just sufficient to maintain the particular pressure differential across servo piston 50 as selected by the capsule metering force. There is a finite and stable position for skew shaft 49 for each combination of manifold pressure and temperature thereby establishing the relationship wherein the quantity of fuel delivered to the engine per revolution is proportional to manifold air density.

=Fuel injection pump 20 contemplates operation at engine speed and therefore the number of metering chambers employed in plunger block 29 is one-half the number of cylinders in the engine and it is assumed that the engine operates on the usual four-stroke cycle. Reference is now made specifically to FIG. 6 wherein the structure illustrated therein is furnished with three mutually spaced apart metering chambers 31, 32, 32a to accommodate a six cylinder engine. This figure illustrates the path of travel traced out by one of the valve arcuate slots 37 with respect to metering chamber 31 and the open port ends 42a, b, of its correlated discharge passages for normal pump operation. Metering chambers 31, 32, 32a and the open ended metering passages thereof 31', 32', 32a, of which the open ends lie in the plane of plunger bearing face 27, are shown in end phantom.

The embodiment of FIG. 6 contemplates use with a six cylinder engine, hence, six discharge passages 42 are suitably disposed in a convenient manner in distributor block 30. The open ends 42a, b, c, d, e, f of discharge passages 42 are shown in dashed lines in FIG. 6, and they lie in the plane of bearing face 23. Discharge passages 42 are grouped in pairs, wherein each pair is operatively associated with a respective metering chamber 31, 32, 32a. The ports of each pair of discharge passages lie equidistant and on opposite sides of a radial line bisecting its correlated metering chamber. Although FIG. 1 shows the structural detail with respect to only one of such discharge passages, it will he understood that each passage 42 terminates with a threaded connecter portion 75 to permit coupling with a respective fuel supply line 43. The other ends of supply lines 43 terminate in nozzles (not shown herein), operatively associated with respective engine cylinders in the customary manner.

Upon rotation of drive shaft 25 and eccentric 35 in the direction indicated by arrow 76, the arcuate slot 37 next to communicate with metering chamber 31 traces a path of motion as indicated by reference letters a, b, c, d n, 0, p, q. At the time slot 37 is undergoing travel through the segment depicted by d, e, f, the outer periphery 36 of valve 34 is spaced from the portion of toothed annulus 40 of gear ring 39 to expose chamber 31 to the crescent shaped opening 41. Fuel under pressure enters metering chamber 31 via crescent area 41 and chamber port 31' at which time plunger 45 is undergoing its intake stroke to charge chamber 31 with fuel. As drive shaft 25 continues rotation valve 34 moves in a direction to close metering chamber 31 thereby shutting off communication with the pressurized crescent area 41 and thus trapping the fuel filled in chamber 31. For a brief interval, the fuel remains trapped in chamber 31. Further rotation of valve 34 carries arcuate slot 37 toward the outer edge 31' of chamber 31. Thereafter slot 37 experiences a segment of travel as it overlaps the filled metering chamber 31. The foregoing is depicted in the figure by references g, h, i, j, k. While slot 37 is in register with metering chamber 31, the synchronized plunger 45 is undergoing its discharge stroke. Simultaneously, or somewhat previously to this occurrence, drilling 38 in slot 37 will have overlapped one of the discharge passage ports such as 42a so that at the moment when the outer edge of the arcuate slot 37 registers with metering chamber 31, said metering chamber is placed in communication with the discharge passage operatively associated with port 42a to permit discharge of fuel to the engine cylinder connected thereto.

With further rotation of drive shaft 25, slot 37 recedes from chamber 31 and completes its cycle of travel as depicted by references I, m, n, 0, p, q as valve '34 recedes from metering chamber 31 to form the crescent shaped area 41 so as to expose chamber 31 to fuel intake 44 in order to refill chamber 31 for the next revolution of operation.

During the foregoing described pump operation, the other discharge passage of the correlated pair is closed off to metering chamber 31. Its port 42b does not register with slot drilling 38 but, instead, remains covered by the valve facing as said facing laps against bearing face 28. It will be understood that the other chambers 32 and 32a also experience a similar operational relationship with the arcuate slots in valve 34 although this is not shown in the figures, with the result that for successive revolutions of drive shaft 25 each metering chamber is individually interconnected in a desired sequence alternately with the fuel intake port 44 and then with one and then the other of its correlated discharge passages as the pump undergoes normal operation of fuel distribution.

Bearing faces 27, 28 of plunger block and distributor block are each provided with three mutually spaced apart spillway passages 77 to 79 and 83 to 82 extending along radial lines with respect to axis 33. Spillway passages 77 to 79 in plunger bearing face 27 are angularly spaced similar distances from respective chambers 31, 32. 32a and extend radially a sufficient distanec so that the outer ends of passages 77 to 79 register with crescent shaped area 41 when said area is developed thereat. Similarly, spillway passages 80 to 82 on distributor bearing face 28 are also angularly spaced equal distances from respective chambers 31, 32, 32a and likewise extend radially a sufficicnt distance to permit register with crescent shaped area 41. A spillway passage from each group form a pair operatively associated with respective ones of metering chambers 31, 32, 32a and each passage of such pair lies on opposite sides of a radial line bisecting the correlated metering chamber.

Spillway passages 77 to 79 are angularly spaced a preselected distance from respective metering chambers so that the passages lie outside the path of travel of arcuate slots 37 for the foregoing described pump operation with the result that during normal pump operation as depicted in FIG. 6, spillway passages 77 to 79 do not interfere by registering with the metering chambers. Spillway passages 82 in distributor bearing face 28 are similarly disposed so as not to interfere with the foregoing described normal pump operation. When drilling 38 of one of the arcuate slots registers with passages 80 to 82 as illustrated in FIG. 6, as slot 37 sweeps past segments 0, p, q, said slot is no longer in communication with its correlated metering chamber. Thus fuel cannot be released to spillway passages 80-82 via a slot drilling 38 even though the slot thereof for an interval of time overlaps such passage. On the other hand, drilling 38 of the next slot in the sequence is at the opposed slot end. Consequently, spillway passages 80'82 are normally closed to the metering chambers of the pump.

During operation of pump 20 as depicted in FIG. 6, gear ring 39 is held stationary by being locked in position by locking means to be described hereinafter. Pump 20 is switched to its fuel cutoff phase of operation by allowing gear ring 39 to turn approximately sixty seven degrees and then maintaining same stationary as valve 34 undergoes its hypotrochoid motion. Upon release of the locking means, gear ring 39 will rotate by the transfer of frictional force from the rotating drive shaft 25. Turning of gear ring 39 causes angular displacement of valve 34, and because of the 9:8 gear ratio, valve 34 will rotate about its own center approximately seventy five degrees. Such rotation will properly time phase slots 37 for cutoff operation because it shifts valve 34 so that each of the slots thereof is shifted fifteen degrees from the normal pump operating position that would have been occupied by a similarly phased slot, that is to say, a slot two removed therefrom. The aforesaid fifteen degree departure from normal pump operation position will cause one end of the kidney slots 37 to register individually with spillway passages 77, 78, 79 as the other ends thereof register with the correlated metering chambers 31, '32 and 32a. The operating relationship of the six spillway slots, the three metering chambers and the eight kidney slots 37 for cutolf operation is illustrated in FIG. 7.

FIG. 7 illustrates the path of travel a, b, c n, 0, p, traced out by one of the arcuate slots 37 with respect to metering chamber 31, discharge ports 42a, b of the correlated discharge passages 42 and spillway passages 7782 as drive shaft 25 undergoes one revolution of turning in the direction indicated by arrow 76. As arcuate slot 37 passes through a sector corresponding to c, d and e, valve 34 has receded from gear ring 39 to expose metering chamber 31 to crescent shaped area 41 at which time chamber plunger 45 is undergoing its intake stroke to cause said chamber to fill with fuel. Upon further turning of shaft 25 through the sector corresponding to 7, g, h, i, it will be noted that spillway passage 77 communicates with the arcuate slot prior to and during a period of time said arcuate slot registers with metering chamber 31. By the time chamber 31 registers with the arcuate slot it has ceased communication with crescent shaped area 41 and plunger 45 is experiencing a discharge stroke to relieve chamber 31 of fuel. The fuel flowing from metering chamber 31 returns to crescent shaped area 41 via spillway passage 77. Area 41 is still in register with the outer end of spillway passage 77 although long before this occurrence area 41 has ceased to register with metering chamber 31 by reason of the fact that the outer end of spillway passage 77 is angularly separated a suitable distance from metering chamber 31. For the particular illustration of FIG. 7, drilling 38 is in the left-hand end of the slot 37 in which case drilling 38 does not register with discharge passage port 42a as slot 37 traces out its aforesaid path of travel. However, if drilling 38 were in register with discharge passage port 42a, fuel will still port back to the fuel input supply 44 rather than to the engine cylinder for the reason to be explained hereinafter. Further rotation of valve 34 sweeps slot 37 through a sector corresponding to j, k, l 0, p during which time metering chamber 31 is again exposed to area 41 to receive fuel from supply 44. As seen from FIG. 7 discharge port 42b and spillway passage 80, both in hearing face 28, do not interfere with the aforesaid operation. Port 4% does not come into register with slot 37 via drilling 38 thereof until after said slot has receded from chamber 31. Whereas spill passage 88 misses communication with chamber 3 1 as slot drilling 38 sweeps adjacently thereby.

Upon the next cycle of revolution of drive shaft 25, the next slot in the sequence is brought into register with metering chamber 31, but in this instance the drilling thereof is at the right-hand end of the slot. As before, the inner end of passage 77 registers with the slot prior to and during a period of time metering chamber 31 is in register with said slot. This is depicted in FIG. 7 by d, e, f, g, h, i. During the latter portion of the aforesaid travel, the outer end of passage 77' communicates with crescent area 41 as the metering chamber 31 releases the fuel trapped therein. During the aforesaid sector of travel there exists a period during which drilling 38, now at the right-hand side of the slot in register with chamber 31, also registers with discharge port 42a. Fuel continues to port into spillway passage 77 by reason f the fact that the back pressure existing in the fuel supply line 4 3 leading from the coupled discharge passage 42 and to the engine cylinder connected therewith is much greater than the back pressure in the fuel input passage 44. Consequently fuel returns to fuel input supply 44 in the manner described hereinbefore.

It will also be observed that port 42b and spillway passage 80 in bearing face 28 do not interfere with the aforesaid mode of operation since said port and passage do not register with drilling 38 in the right-hand side of slot 37 as it sweeps adjacently thereby.

With further rotation of valve 34 slot 37 completes its trace, i, k, l p. While slot 35 is in the vicinity of k, l, m, metering chamber 31 is again exposed to crescent shaped area 41 to receive fuel for the next revolution of operation.

Although not shown in FIG. 7 it will be understood that the other chambers 32 and 32a also experience a similar operational relationship with respect to arcuate slots 37 in valve 34, with the result that upon successive revolutions of drive shaft 25, each metering chamber is individually interconnected alternately with the fuel supply intake line 44 and then with its correlated spillway passage, 77 or 78 or 79, to effect fuel cutoff operation. Consequently as long as gear ring 39 is held stationary in the position depicted in FIG. 7, substantially sixty seven degree from its initial position corresponding to normal pump operation, fuel, instead of being released to respective engine cylinders, is returned to the fuel supply line 44.

Fuel pump is returned to normal operation by shifting gear ring 39 preferably in like sense a further amount of approximately thirteen degrees which shift when added to the first shift of sixty seven degrees will have caused gear ring 39 to experience an aggregate displacement of eighty degrees. This in turn will have imparted an overall displacement of ninety degrees to valve 34 by reason of the eight to nine gear ratio therebetween. Since valve 34 has eight arcuate slots 37 and alternate ones are alike, a ninety degree shift to valve 34 returns same to the time phase it experienced prior to initiation of fuel cutoff operation.

Gear ring 39 is held stationary by locking structure during normal and cutoff operation. Release of gear ring 39 allows it to undergo angular displacement to cause pump 20 to alternate from one to the other of the aforesaid operations. Reference is now made to FIGS. 2, 3 and 4 for such locking structure which includes a rotatable pinion '85 recessed in housing 21. Pinion 85 has an annulus of teeth 86 adapted to engage toothed annulus 53 on the outer periphery of gear ring 39. By choosing a gear ratio of 1:45, a three hundred sixty degree turn of pinion produces an eighty degree turn of ring 39. Pinion 85 is mounted and keyed to a shaft 87 supported for rotation in housing 21. A locking wheel 88 is also mounted and keyed to shaft 87 and is provided with a locking tongue 89. Pinion 85 and locking Wheel 88 are mounted in spaced relationship on shaft 87 and turn therewith. A rocking arm 90 is provided with first and second spaced teeth 91, 92 suitably disposed so that tongue 89 is adapted to engage alternately one and then the other of teeth 91, 92.

Rockable arm 90 is suspended by a shaft 93 to rock about the axis thereof under the force supplied by a compressed spring 94 mounted on a guide pin 95 supported from arm 90 as seen best in FIG. 2. The other spring end is seated in a recess 108 located in a portion of housing structure 21. Locking tongue 89 is normally engaged by tooth 92 to prevent rotation of shaft 87 which maintains pinion 85, and thus gear ring 39, stationary for normal delivery position. Tooth 92 will release locking tongue 89 upon rocking of arm 98 when solenoid 98 is suitably energized. The energizing signal is controlled by the vehicle operator, and when applied causes downward motion of plunger 97 which rocks arm 98 counterclockwise in the direction of arrow 96 (FIG. 2) wherein tooth 92 releases tongue 89 so as to free gear ring 39 for movement. Gear ring 39 now rotates under the force transmitted thereto by drive shaft 25 as shaft 25 undergoes rotation in direction of arrow 76. Moreover the turning gear ring 39 also rotates pinion 85. Movement of arm 90 is halted by a set screw 101 fixed to the end of arm 90 and adapted to engage the adjacent housing structure. Proper setting of screw 10-1 will prevent tooth 91 rubbing against the periphery of locking wheel 88 during actuation into cutoff operation. The released locking wheel 88 and pinion 85 revolve in the direction of arrow 99 until halted by reason of engagement of tongue 89 and tooth 91 (as shown in FIGS. 2 and 4) which tooth has moved by reason of turning of arm 90 into the line of travel of tongue '89 to engage same and hold wheel 88 and pinion 85 and thus gear ring 39 stationary so as to effect cutoff operation. The aforesaid movement of wheel 88 and pinion 85 and thus gear ring 39 is predetermined by the spacing between teeth 91, 92.

Tooth 91 is suitably disposed from tooth 92 to allow an angular displacement of gear ring 39 through the aforesaid sixty seven degrees, which in turn allows valve 34 to shift approximately seventy five degrees so as to place valve 34 in position to effect cutoff mode of operation depicted in FIG. 7. Cutoff operation will continue as long as solenoid 98 remains energized. Withdrawal of the signal by the vehicle operator rocks arm 90 in the direction of arrow 96' (FIG. 4) to return same to its initial position under the force of spring 94 as solenoid plunger 9-7 withdraws upwardly which releases locking tongue 89 from engagement with tooth 91. This action frees locking wheel 88 and thus pinion 85 to rotate in the direction of arrow 99 under the force transmitted thereto by gear ring 39. Gear ring 39 is now free to turn the aforesaid thirteen degrees in the direction of arrow 76 under the force transmitted thereto by drive shaft 25. Movement of gear ring 39 is brought to a halt upon engagement of the advancing locking tongue 89 with tooth 92 as pinion completes its cycle of revolution to cause pump 20 to return to normal fuel distribution operation.

During actuation into cutoff operation, there exists a position wherein valve slots 37 are neither in register with the discharge ports 42a, b e, 1 nor the spillway passages 77, 78, 79 to allow any one or more of the fuel charged metering chambers to release the fuel trapped therein. Consequently, it is desirable to furnish spillway passages 80, 81, 82 suitably disposed in the distributor block face 28 so as to relieve the charged metering chambers during this otherwise hydraulic locking condition.

Spillway passages 80, 81, 82 serve to return fuel to intake supply 44 as the metering chambers communicate therewith via drillings 38. For the six-cylinder pump, it was found that hydraulic lock may be avoided by locating an auxiliary spillway passage 80, 81, 82 twenty three degrees from a correlated metering chamber but on the opposite side of the chamber with respect to its respective passages 77, 78 or 79. It will be seen upon observing FIGS. 1 through 4 that locking Wheel 89, rockable arm 90 and solenoid 98 are suitably disposed near one end of housing 21 whereas pinion 88 is supported substantially coplanar with valve 34 at the other end of housing 21, thus necessitating a relatively long shaft 87 suitably mounted in a convenient manner in housing 21 and extending between wheel 89 and pinion 88.

It Will be understood from the foregoing description of pump operation that the first group of spillway passages 77 through 79 and the second group of such passages 80 through 82 are suitably disposed in respective bearing surfaces 27, 28 in order that said passages register with metering chambers 31, 32, 3211 via valve ports 37 at the desired moment of pump operation. Typical dimensional specifications for such passages for the six-cylinder engine now will be set forth for illustrative purposes. In the {first place it will be understood that valve disc 34 may be of conventional design. It has been found that spillway passages satisfactorily serve the purposes outlined therefor when a pair of such passages, one from each group, lie on opposite sides of and are equally spaced twenty three degrees from a radial line bisecting the respective metering chambers. The dimension of twenty three degrees is illustrated by angle in FIGS. 6, 7. In addition it has been found that said passages may be formed by grooves having width of .02 inch in the plane of their respective bearing surfaces and may extend approximately .062 inch into distributor and plunger blocks respectively.

Cutoff operation in a fuel injection pump requires means for supplying torque to rotate gear ring 39 and pinion shaft assembly 85, 87. One basic advantage of the instant invention is that the torque required to turn gear ring 39 and correspondingly rotate pinion shaft assembly 85, 87 is actually supplied by the automobile engine itself, or the starter motor via drive shaft 25. Drive shaft transmits the turning force to gear ring 39 by reason of the frictional forces developed on valve 34 as said valve rotates on eccentric 33. This causes gear ring 39 to rotate in the same direction as main shaft rotation. Since the frictional force on valve 34 increases as drive shaft r.p.m. decreases, the required torque to effect turning of gear ring 39 increases for the lower engine speeds. A small torque, slightly less than a poundinch, is required at the relatively high engine speeds of 800 to 1000 rpm. When cutoff is used to purge the engine at cranking speeds in the order of fifty rpm. the torque requirement rises sharply to approximately five pound-inches. High torque is also required when the engine is brought to a stop in cutoff position, thus it becomes necessary to rotate gear ring 39 at cranking speeds when starting up the engine. A rotary solenoid, motor actuator, servo gear motor, or other similar but external devices are impractical to meet the high torque loads because of the relatively large size of such units, Whereas the application of pump 20, particularly in automotive installations, must meet small space restrictions.

Consequently, in addition to providing the advantage of furnishing the drive torque by the engine itself whereby external sources of torque are eliminated, the invention also permits the construction of a compact fuel pump where space requirements are very much restricted.

The force necessary to effect escapement of rocker arm teeth 91, '92 with respect to looking tongue 89 should be great enough to overcome (l) the friction between the contacting surfaces of said tongue and teeth, and in addition, (2) the force necessary to overcome spring 94 at the time arm 90 is rocked. A preferred method of supplying the force for effecting such escapement is that illustrated herein, wherein a continuous duty solenoid 98 is provided to operate rocker arm by means of solenoid plunger 97 travelling a linear distance of .06 inch. The frictional force between locking tongue 89 and teeth 91, 92 has been calculated to be approximately 37.5 ounces so that a force of 50 ounces would be adequate to effect escapement. Doubling this force to overcome return spring 94 would establish a minimum force requirement of ounces or 6 .25 pounds. A solenoid furnishing lineal plunger movement of .06 inch and capable of developing at least 6.25 pounds over such travel, would meet the minimum work requirement to satisfy the aforesaid escapement operation. In an automotive installation incorporating the invention a solenoid of one and seveneighth inches in diameter and one and seven-eighth inches long satisfactorily met the aforesaid requirements. An electrical system for energizing the solenoid may include a generator driven by the engine. The electrical system employed in the foregoing installation furnished 24 volts to energize the solenoid which produced a twenty-nine pound force at such voltage. The voltage source provided eighteen volts at the lower cranking speed at which time the solenoid provided a twenty-pound force through its .06 inch movement. At the most unfavorable operating conditions, which would be high temperature operation in the order of F., the output force furnished by the solenoid was in the neighborhood of twelve or thirteen pounds for the .0 6 inch movement which still met the work requirement to accomplish escapement of rocker arm 90.

FIGS. 8 and 9 depict the use of the invention in an eight-cylinder pump. In basic respects the eight-cylinder pump is the same as the foregoing described apparatus except for the necessary changes to accommodate two additional engine cylinders. Plunger block 29 is furnished with four suitably spaced apart metering chambers 131, 132, 132a, 1321?. Each of the said chambers has a pair of correlated ports 142a, b, c, d, e, f, g, 11, associated with respective ones of the eight discharge passages 142 now employed. The four metering chambers of the eight-cylinder pump are not symmetrically spaced apart. Consequently, during normal pump delivery, fuel will feed from one pair of the chambers into like ends of valve slots 37 as these slot ends come into overlapping position with said pair of chambers whereas fuel will feed into valve slots 37 as the opposite ends of the slots come into Overlapping position with the other pair of chambers. Accordingly, a discharge port is located to the left of the chamber center lines for one pair of metering chambers and to the right of the chamber center lines for the other pair. The problem of hydraulic lock does not occur in the eight-cylinder pump. Thus, the pump does not include a second group of spillway passages corresponding to 80, 81, '82 of the six-cylinder pump embodiment.

The eight-cylinder pump has four spill passages 177, 178, 179, 179a in the plunger block bearing surface for returning fuel to the intake supply 44 during cutoff. Each spill passage is spaced a suitable distance away from its correlated metering chamber so as to locate properly the spill passage with respect to the moving valve slots 37 and the interconnected chambers at the time gear ring 39 has been shifted to effect cutoff operation. Each spill passage 177, 178, 179, 179a is spaced approximately fourteen degrees from a radial line bisecting its correlated chamber. The fourteen degree dimension is indicated as 0: in FIGS. 8, 9. As shown in these figures, two of said passages form a pair lying between an are described by the obtuse angle B separating their respective chambers, whereas the other two passages form a pair lying outside an are described by the obtuse angle 6 separating their respective chambers. The angle [3 is one hundred degrees; i.e., the center line of each metering chamber is fifty degrees from the vertical center line through the structure shown in FIG. 8. The width and 13 depth dimensions of spill passages 177, 178, 179 and 179a may be substantially the same as that specified for the six-cylinder pump.

FIG. 8 illustrates the trace made by one arcuate valve slot 37 for one revolution of drive shaft at the time pump 20 is set for normal operation and thus depicts pump operation corresponding to that shown in the illustration of FIG. 6. For example, as slot 37 traces out travel a, b, c s, t, u, metering chamber 131 is first exposed to receive fuel. Thereafter slot 37 approaches and then registers with said metering chamber in order to interconnect same with the discharge passage operatively associated with port 142a to allow fuel to flow to a correlated engine cylinder. Drilling 38 is shown in the right-hand side of slot 37 in these figures. As valve 34 continues its travel, valve slot 37 recedes from metering chamber 131 so as to expose said chamber to crescent area 41 for refilling as the next slot in the series traces out the aforementioned path of travel wherein communication is effected with port 14212 of the other discharge passage of the correlated pair. Spill slots 177, 178, 179 and 179a do not interfere with the operation as depicted in FIG. 8 as each chamber is individually interconnected in a desired sequence alternately with the fuel supply 44 and then with one and then the other of its correlated discharge passages 142 as pump 20 undergoes normal operation of fuel distribution for successive rotations of drive shaft 25.

Cutoff operation as depicted in FIG. 9 is brought about in the same manner as described in the foregoing with respect to the six-cylinder engine. Gear ring 39 is displaced sixty-seven degrees to shift valve 34 a correlated amount. Sixty-seven degree movement of gear ring 3% in one direction will shift the hypotrochoid moving valve slots 37 completely out of overlap engagement with two of the metering chambers. For this reason spillway passages for one pair of chambers are disposed to the left of their correlated chambers whereas the other pair of spillway passages are disposed to the right of their correlated chambers. As a result of the foregoing arrangement, before two similarly phased slots 37 leave overlapping cutoif engagement with respect to one pair of metering chambers, valve slots of opposite phase (that is to say, slots with drillings at the other or opposite ends) will begin cutoff engagement with the other pair of metering chambers. As valve 34 carries out its hypotrochoid motion, the charged metering chambers are interconnected with respective spillway passages 177, 178, 179, 179a via arcuate slots 37 to return fuel to input supply 44 rather than to the engine cylinders. FIG. 9 illustrates the path of travel a, b, c, d l, m, n traced out by one of the slots 37. It Will be assumed that the drilling thereof is at its right-hand end as seen in the figure. During the time slot 37 negotiates the sector corresponding to a, b, c, metering chamber 131 will have completed its fuel discharge into its correlated spill passage 177 via the immediately preceding slot of the series which has its drilling at its left end. As slot 37 continues through d, e, f metering chamber 131 is exposed to crescent shaped area 41 to be charged with fuel. For the next sector of travel h, i, j, k, slot 37 moves into register with spill passage 177 and at the same time or soon thereafter said slot also registers with metering chamber 131 which is now no longer exposed to crescent shaped area 41 but discharging the fuel trapped therein. The fuel is returned to fuel supply 44 via spill passage 177 while the outer end of spill passage 177 still communicates with crescent shaped area 41. During the last phase of the trace 1, m, n, metering chamber 131 is exposed to receive fuel in order to accommodate the next revolution of drive shaft turning. Upon additional displacement of gear ring 39 through thirteen degrees, pump 20 is returned to normal operation as described hereinbefore. As noted hereinbefore, as gear ring 39 is shifted in increments an aggregate of eighty degrees, pump 20 will alternately shift from 14 normal fuel distribution to cutoff operation and return to normal operation.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made Without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a pump for distributing metered quantities of fuel to an internal combustion engineand employing a pump housing having an internal cavity formed in part by opposed parallel bearing surfaces separating the plunger block portion of said pump housing from the distributor block portion thereof, wherein said housing also includes an intake port communicating with a source of fuel under pressure, a plurality of metering chambers arranged about a common axis wherein each chamber has an open ended metering passage in the bearing surface on the plunger block side of said cavity, a reciprocating plunger in each chamber, a plurality of discharge. passages in said distributor block for supplying fuel to a corresponding number of engine cylinders and communicating with the bearing surface on the distributor block side of said housing, the combination of a ported disc shaped valve mounted eccentrically and seated between said opposed bearing surfaces, an annulus of teeth on the outer periphery of said valve, a gear ring having an inner toothed annulus surrounding said valve and meshing with said valve teeth, said gear ring being mounted between said bearing surfaces for rotation about said axis, means imparting hypotrochoid motion to said valve in respect to said axis as the teeth thereof engage said gear ring, said gear ring mounted for rotatable displacement alternately from one to another of a plurality of positions, means for locking said gear ring in such positions, one of said bearing surfaces also having a plurality of spillway passages correspond ing to the number of metering passages and adapted to register with the fuel input port, each spillway passage being in spaced relationship with respect to a correlated metering chamber whereupon said spillway passages lie outside the path of travel of valve ports provided in said ported disc-shaped valve when said gear ring is held in certain of its positions and as said chambers are individually interconnected in a desired sequence alternately with the fuel intake port and one and then the other of correlated ones of said discharge ports during valve movement, said interconnection between the metering chambers and the discharge ports being effected by said valve ports, means for repositioning said gear ring to the other of its positions to cause correlated orientation of said valve to bring said spillway passages into register sequentially with said valve ports upon interconnection of same with respective ones of said chambers during the discharge stroke of the plun gers thereof to cause the return of fuel to the fuel intake port as said valve undergoes turning movement, said successive displacements of said gear ring from one to another of its plurality of positions being in like sense.

2. Apparatus as defined in claim 1, said means for imparting hypotrochoid motion comprising, a drive shaft for said pump, and an eccentric keyed to said drive shaft, said valve being mounted on said eccentric and slidably turning thereon as the outer annulus of valve teeth meshes with the inner toothed annulus of said gear ring so as to impart said hypotrochoid motion to said valve wherein the torque required to turn said gear ring from one to another of the plurality of its positions is furnished by the turning force derived from said drive shaft.

3. Apparatus as defined in claim 1 wherein, said valve ports include mutually spaced apart arcuate slots along the valve surface lapping the bearing surface containing said spillway passages, alternate ones of adjacent ends of said slots having passages extending through said valve and communicating with the valve surface lapping the other of said bearing surfaces, said valve teeth and meshing gear ring teeth having an 8 to 9 gear ratio, wherein said gear ring is rotationally displaceable an increment of approximately sixty seven degrees from said certain positions to cause correlated shift to said valve to effect fuel cutoff operation, and wherein said gear ring is rotationally displaceable in like sense a further increment of approximately thirteen degrees to cause correlated shift to said valve to effect normal pump operation.

4. In a pump for distributing metered quantities of fuel to an internal combustion engine and employing a pump housing having an internal cavity formed in part by opposed bearing surfaces separating the plunger block portion of said pump housing from the distributor block portion thereof, wherein said housing also includes an intake port communicating with a source of fuel under pressure, a plurality of metering chambers arranged about a common axis wherein each chamber has an open ended metering passage in the bearing surface on the plunger block side of said cavity, a reciprocating plunger in each chamber, a plurality of discharge passages in said distributor block for supplying fuel to a corresponding number of engine cylinders and communicating with the bearing surface on the distributor block side of said housing, the combination of a ported disc shaped valve mounted eccentrically and seated between said opposed bearing surfaces, an annulus of teeth on the outer periphery of said valve, a gear ring having an inner toothed annulus surrounding said valve and meshing with said valve teeth, said gear ring being mounted between said bearing surfaces for rotation about said axis, means imparting hypotrochoid motion to said valve in respect to said axis as the teeth thereof engage said gear ring, said valve teeth and meshing gear ring teeth having a predetermined gear ratio, one of said bearing surfaces also having a plurality of spillway passages corresponding to the number of chambers, each spillway passage being adapted to register with the fuel input port and being preselectedly spaced from correlated chamber for conducting fuel therefrom to said fuel input port during a fuel cutoff phase of operation of said pump, said gear ring mounted for rotatable displacement alternately from one to another of a plurality of positions, means for locking said gear ring in such positions, means for rotational displacement of said gear ring through a preselected increment from a first position to cause correlated orientation of said valve to effect fuel cutoff operation wherein said spillway passages sequentially register with valve ports provided in said ported disc-shaped valve upon interconnection of same with respective ones of said metering chambers during discharge stroke of the plungers thereof to return fuel to said fuel intake port as the valve undergoes hypotrochoid movement, and means for rotational displacement of said gear ring in like sense through a further preselected increment to cause correlated orientation of said valve wherein said spillway passages lie outside the path of travel of said ports such that said chambers are individually interconnected by said valve ports in a desired sequence alternately with the fuel intake port and certain of said discharge ports as said valve undergoes its turning movement.

5. Apparatus as defined in claim 4 wherein, said spillway passages are in the plunger block bearing surface, said valve teeth and meshing gear ring teeth have an 8 to 9 gear ratio, said gear ring is rotationally displaceable an increment of approximately sixty seven degrees from said first position to cause corresponding shift of said valve to cutoff operation, and said gear ring is rotationally displaceable in like sense a further increment of approxi mately thirteen degrees to cause the valve to assume normal pump operation.

6. Apparatus as defined in claim 4 wherein, said gear ring has an annulus of teeth on its outer periphery, a pinion engaging the said annulus of teeth, and means for rotatably displacing said pinion alternately from a first iii to a second of two positions, rotational movement of said pinion from the first to the second of its two positions converts normal pump operation to fuel cutoff operation and further rotational movement of said pinion in like sense returns same to the first of its positions and similarly returns the pump to normal operation.

7. Apparatus as defined in claim 6 wherein, the gear ratio between said pinion and outer peripheral toothed annulus of said gear ring is preselected so that one complete revolution of said pinion converts normal pump operation to cutoff operation and returns the pump to normal operation.

8. Apparatu as defined in claim 4 wherein, said gear ring has an annulus of teeth on its outer periphery, a pinion engaging the outer peripheral annulus of said gear ring, a shaft mounted for rotation, a wheel having a locking tongue, said pinion and wheel being mounted in spaced relationship on said shaft and turnable therewith, a rockable arm having first and second spaced teeth for engaging alternately said locking tongue, said locking tongue being engaged by one and then the other of said teeth to prevent shaft rotation except during rocking of said arm, and means for rocking said arm so that one tooth of said arm releases said tongue to permit shaft and pinion rotation until halted by engagement of said locking tongue with the other tooth of said arm, successive increments of rotation of said shaft and pinion permit corresponding gear ring movements so that pump operation alternates correspondingly from normal operation to fuel cutoff operation.

9. Apparatus as defined in claim 8, said means for imparting hypotrochoid motion comprising, a pump drive shaft, and an eccentric keyed to said drive shaft, said valve being mounted on said eccentric and slidably turning thereon as the outer annulus of valve teeth meshes with the inner toothed annulus of said gear ring so as to impart said hypotrochoid motion to said valve wherein the torque required for turning said gear ring and pinion and locking wheel assembly upon release of said locking tongue is furnished by the turning force derived from said drive shaft to effect a relatively self-contained pump.

10. Apparatus as defined in claim 8 wherein said rocking means comprising, a solenoid having a movable plunger for pivoting said rockable arm from one to another of two positions, and means for actuating plunger movement to effect escapement of said locking tongue with respect to one and then the other of said rockable arm teeth to permit corresponding turning of said pinion and gear ring, whereby pump operation alternates from normal operation to fuel cutoff operation.

11. In a pump for distributing metered quantities of fuel to an internal combustion engine and employing a pump housing having an internal cavity formed in part by opposed bearing surfaces separating the plunger block portion of said pump housing from the distributor block portion thereof, wherein said housing also includes an intake port communicating with a source of fuel under pressure, a plurality of metering chambers arranged about a common axis wherein each chamber has an open ended metering passage in the bearing surface on the plunger block side of said cavity, a reciprocating plunger in each chamber, a plurality of discharge passages in said distributor block for supplying fuel to a corresponding number of engine cylinders and communicating with the bearing surface on the distributor block side of said housing, the combination of a ported disc shaped valve mounted eccentrically and seated between said opposed bearing surfaces, an annulus of teeth on the outer periphery of said valve, a gear ring having an inner toothed annulus surrounding said valve and meshing with said valve teeth, said gear ring being mounted between said bearing surfaces for rotation about said axis, means imparting hypotrochoid motion to said valve in respect to said axis as the teeth thereof engage said gear ring, the plunger block bearing surface also having a plurality of spillway passages corresponding to the number of chambers, said passages extending radially from said axis and being adapted to communicate with the fuel intake port, said valve teeth and meshing gear ring teeth having a predetermined gear ratio, each spillway passage being spaced a preselected angular distance from a radial line bisecting a correlated chamber, said gear ring mounted for rotatable displacement alternately from one to another of a plurality of positions, means for locking said gear ring in such positions, means for imparting rotational displacement of said gear ring through a preselected increment from a first position corresponding to normal fuel distribution operation to cause a corresponding shift to said valve to effect cutoff operation as said spillway passages sequentially register with said valve ports upon interconnection of same with respective ones of said metering chambers during the discharge stroke of the plungers thereof to return fuel to said fuel intake port as said valve undergoes hypotrochoid movement, and means for imparting rotational displacement of said gear ring in like sense through a further preselected increment to cause corresponding shift of said valve such that said spillway passages lie outside of the path of travel of said valve ports wherein said chambers are individually interconnected by said valve ports in a desired sequence alternately with the fuel intake port and certain of said discharge ports as said valve undergoes hypotrochoid movement to return said pump to normal operation, said distributor block bearing surface also having a plurality of spill passages corresponding to the number of metering chambers, the last-mentioned passages extend radially from said axis and being adapted to communicate with the fuel intake port, each of said distributor bearing surface passages being spaced a preselected angular distance from a correlated metering chamber for con ducting fuel therefrom to the fuel input port as each of said passages registers with a valve port provided in said ported disc-shaped valve at the time said correlated chamber is discharging fuel trapped therein and is otherwise not in communication with the fuel intake port or an engine cylinder to prevent hydraulic lock.

12. Apparatus as defined in claim 11, wherein, said plunger block includes three metering chambers to accommodate a six cylinder engine, said valve teeth and meshing gear ring teeth have an 8 to 9 gear ratio, there are three spillway passages in each of said plunger and distributor bearing surfaces, one passage of each group defining a pair operatively associated with a correlated metering chamber, and each passage of a pair being spaced equidistantly approximately twenty-three degrees on opposite sides of a radial line bisecting their correlated chamber.

13. In a pump for distributing metered quantities of fuel to an internal combustion engine and employing a pump housing having an internal cavity formed in part by opposed surfaces separating the plunger block portion of said pump housing from the distributor block portion thereof, wherein said housing also includes an intake port communicating with a source of fuel under pressure, four metering chambers suitably arranged around a common axis wherein each chamber has an open ended metering passage in the bearing surface on the plunger block side of said cavity, a reciprocating plunger in each chamber, eight discharge passages in said plunger block for supplying fuel to a corresponding number of engine cylinders and communicating with the bearing surface on the distributor block side of said housing, the combination of a ported disc shaped valve mounted eccentrically and seated between said opposed bearing surfaces, an annulus of teeth on the outer periphery of said valve, a gear ring having an inner toothed annulus surrounding said valve and meshing with said valve teeth, said valve and gear ring having an eight to nine gear ratio, said gear ring being mounted between said bearing surfaces for rotation about said axis, means for imparting hypotrochoid motion to said valve in respect to said axis as the teeth thereof mesh with said gear ring teeth, said plunger block bearing surface also having four spillway passages extending radially from said axis and being adapted to communicate with the fuel intake port, each spillway passage being spaced approximately fourteen degrees from a radial line bisecting a correlated chamber, two of said passages forming a pair lying between an are described by an obtuse angle separating their respective chambers and the other two passages forming a pair lying outside an are described by an obtuse angle separating their respective chambers, said gear ring mounted for rotatable displacement alternately from one to another of a plurality of positions, means for locking said gear ring in each of such positions, means for imparting rotational displacement of said gear ring through preselected increment from a first position corresponding to normal fuel distributing operation to cause a corresponding shift of said valve to effect cutoff operation as said spillway passages sequentially register with said valve ports upon interconnection with same with respective ones of said metering chambers during the discharge stroke of the plungers thereof to return fuel to said intake port as said valve undergoes hypotrochoid movement, and means for imparting rotational displacement of said gear ring in like sense through a further preselected increment to cause a corresponding shift of said valve such that said spillway passages lie outside of the path of travel of said valve ports wherein said chambers are individually interconnected by said valve ports in a desired sequence alternately with the fuel intake port and certain of said discharge passages to effect normal fuel distribution operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,280,875 Wahlmark Apr. 28, 1942 2,405,938 Beeh Aug. 20, 1946 2,546,583 Born Mar. 27, 1951 2,720,344 Isreeli et al Oct. 11, 1955 2,934,053 Hossack Apr. 26, 1960 2,967,520 Morris Jan. 10, 1961 

